Refrigeration machine circuit with fusion storage

ABSTRACT

A refrigeration machine circuit, comprising a storage mass which gives off its heat of crystallisation at approximately 4*C where the mass is in heat conducting communication with an evaporator of the machine and where the mass has water from a cold water circuit playing on it.

United States Patent ['19 Laing 1 Oct. 23, 1973 REFRIGERATION MACHINE CIRCUIT WITH FUSION STORAGE [76] Inventor: Nikolaus Laing, Hofener Weg 35 bis 37, Aldingen Bei Stuttgart, Germany [22] Filed: May 17, 1972 211 App]. No.: 254,136

[30] Foreign Application Priority Data May 21, 1971 Switzerland 7509/71 [52] US. Cl 62/435, 62/59, 62/434, 62/436, 62/515 [51] Int. Cl. F25d 17/02 [58] Field of Search 62/434, 435, 436, 62/201, 185, 439, 59,139

[56] References Cited UNITED STATES PATENTS 1,891,714 12/1932 Jordan ..62/435 2,271,648 2/1942 Kleist 62/439 2,538,015 1/1951 Kleist.... 62/434 2,538,016 1/1951 Kieist 62/139 2,571,923 10/1951 Morrison 62/434 3,053,060 9/1962 Morrison 62/435 3,271,968 9/1966 Karnath 62/435 3,672,183 6/1972 Bernstein.. 62/436 3,653,221 4/1972 Angus 62/59 Primary ExaminerWi11iam J. Wye Attorney-Willis H. Taylor 'et a1.

[57] ABSTRACT A refrigeration machine circuit, comprising a storage mass which gives off its heat of crystallisation at approximately 4C where the mass is in heat conducting communication with an evaporator of the machine and where the mass has water from a cold water circuit playing on it.

9 C1aims, 7 Drawing Figures PAIENIEu-nm 23 m3 1-? 7 66, 7 52 SHEET 2 or 4 PATENTED UB1 2 3 I973 SHEET 3 BF 4 REFRIGERATION MACHINE CIRCUIT WITH FUSION STORAGE BACKGROUND OF THE INVENTION The efficiency of a refrigeration machine circuit having a condensor and an evaporator which is defined as the heat output divided by compressor drive power or:

in which the temperature of the condensor is T and the temperature of the evaporator is T The efficiency thus depends on the temperature differential between the mean condenser temperature and the mean evaporator temperature and, in accordance with this relationship, increases as the temperatures of the condenser (T and of the evaporator (T approach each other. 7

The temperature of the ambient air rises continuously during the day time isolation period, reaches its maximum value during the afternoon and then again falls back to the original value until the early morning. The difference between the extreme values of the temperature range increases as the sun rises and as the radiation absorption of the atmosphere decreases owing to cloud formation or humidity.

The demand for cooling power increases proportionately to the ambient temperature, whereas the effi-.

ciency of the refrigeration cycle decreases as the ambi-' ent temperature increases.

It is therefore desirable to give off the condenser heat during the coldest hours of the day and to cool a cold water circuit used to cool a room via a heat store from which heat is removed during the night.

In this way up to 50 percent of the energy costs can be saved, and additionally the energy demand occurs during the hours of night, in which in any case off-peak energy is, as a rule, offered at a reduced tariff.

Refrigeration storage devices have become known in which the evaporator is constructed in the form of a register of tubes on which ice is formed The disadvantage consists in that on account of the appreciable expansion of the freezing water, the ice formation causes the water container to burst as soon as the ice envelopes of the individualtubes merge. At the same time thereby the circulation of the waterflowing through the cold water circuit is interrupted precisely atthat point at which most heat is required for re-melting. Moreover the freezing point of the water is-relatively low by comparison with the cold water temperature, so that the thermodynamic efficiency of these machines is poor.

GENERAL, SUMMARY or THE INVENTION.

The invention'eliminates' these disadvantages by means of a refrigeration storage device in which a storage mass used is the hydrate of ionogenic substances having a crystallisation temperature several degrees above the freezing point of the water but below 8 C. Such crystallization temperature will be considerably below the temperature of the cold water circuit utilized for dissipating the heat from the heat exchangers which are exposed to the room temperature and to the refrigeration machine evaporator. In this way not only do the evaporator and condenser temperatures which determine the efficiency move closer together, whereby energy is saved, but moreover the objectionable freezingup of the cold water circuit is effectively prevented.

The containers for the storage mass are, in accordance with the invention, preferably in the form of thin-walled tubes which are suspended vertically and relatively spaced so that the cold water can flow therebetween. The refrigerant evaporates in channels formed between metal plates which extend parallel to the thinwalled tubes and which are in good heat conductive contact with these tubes.

The storage device is discharged during the cool night hours, namely preferably while the cheap tariff applies. During this period the hydrate, which preferably comprises a double saltor mixed hydrate formed from one or more metal salts, crystallises and gives off its heat of crystallisation to the refrigeration machine circuit. For the purpose of supressing the metastable supercooled condition, the hydrate is seeded with seed crystals which are not soluble in the storage mass and which behave isotypically or epitaxially with respect thereto. In order to prevent the seed substance gradually becoming ineffective by reason of stratification, a gel-forming substance, e.g., sodium alginate, is admixed with the storage mass, whereby at the same time the hydrostatic pressure in the lower region of the flexible tubes is considerably reduced. As soon as it is intended to put the machine into operation, the cold water is conducted through the storage devices by means of a pump such that the water gives off the heat which has been removed from the ambient room air to the storage mass.

Preferably the refrigeration machine circuit with respect to the mean cooling load to a condenser temperature is dimensioned so that the condenser tern-. perature-corresponds to the mean temperature of the external ambient air during the hours of cheap tariff in the summer months. During the few extremely hot days, the cooling effect can beproduced by parallel operation of the refrigeration machine during the day.

DESCRIPTION OF THE DRAWINGS l FIG.- l is a diagrammatic view of a refrigeration machine circuit constructed according to the invention;

. FIG. 2 is an enlarged view of a portion of the refriger ation storage device used in the circuit of FIG. 1;

FiG. 3 is an enlarged'cross-secti'on of FIG. Ztaken along line 2-2;

FIG. 4 is an enlarged portion of FIG. 3; I .FIG. 5 is a perspective and partly sectioned view of the storage device utilized in the circuit of FIG. 1; FIG. 6 is an idealized TS-diagram of the refrigeration. machine circuit of FIG. 1; and

' FIG. 7 is agraph illustrating the efficiency of a refrigeration machine circuit constructed according to FIG. 1. I I

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows diagrammatically a cooling circuit in accordance with the invention on the roof of a house or some other location unprotected from thewind. The condenser 1, through which the gas which has been compressed in the compressor 3 is condensed, has air blown through it by the fan 2. The coolant condensate is forced through the conduit 4 into the storage device 5 which forms a unit with an evaporator. The coolant which is there evaporated is returned to the-compressor 3 via the conduit 6.

In the individual rooms (not shown) heat exchangers 7 having fans, 7', 7" are located where the fans are driven by turbines 8, 8', 8". Water is used as the heat carrier and is circulated by means of the circulating pumps 9 whose pressure is also adequate for driving the turbines 8. By means of the three-way valve 10, the water circulation can alternatively be directed through the refrigeration storage device 5 or through the heating boiler 1 1. The return path defined by the water conduits 12 is in communication with the refrigeration storage device 5 as well as the heating boiler 11.

The compressor 3 and the fan 2 are put into operation only during the hours of night. The refrigeration storage device 5 then has the heat which had on the previous day been stored by the water circuit and which originated from the air in the rooms removed.

FIG. 2 shows the structure of an element of the refrigeration storage device 5. An evaporator plate 21 formed from two sheet metal plates soldered together is clamped between two L-shaped sheet metal angle sections 20 and 20. A capillary 23 opens into each of the lower channels 22, the upper channel 24 is connected to a suction pipe connection 25, and both channels are interconnected by vertical channels 26, 26. All the even regions between the channels have perforations 27.

FIG. 3 shows a cross-section corresponding to the section line II-ll to an enlarged scale.

FIG. 4 is a further representation to an enlarged scale of a detail, corresponding to the circle 30 of FIG. 3. The evaporator plate 21 consists of the sheet metal plates 40 and 40 which are soldered together. These evaporator plates are provided with layers defined by foils 31 and 31' which are welded to tubular foils 32 and 32' at their zones of contact. In the region of the perforations 27 the foils 31 and 31 are welded together. The tubular channels which are sealed at their top and bottom ends and which are surrounded by the foils 31 and 32 contain the storage mass 33, whilst the spaces 34 and 35 remaining between the channels have water from the circuit 9, 7, l2 flowing therethrough.

FIG. 5 shows a perspective and partially sectioned view of a storage device. The wall 50 consists of reinforced concrete which is externally insulated by the layer 51. The cover 52 consists of an insulating mass. The L-shaped sheet metal angle sections 20 and 20' rest on the edge53. The suction pipe connections 25 are connected by a manifold 54 which communicates with the conduit 6 (FIG. 1). Water is discharged from the circuit of the storage vessel through the pipe connection 55, whilst the heated water from the water conduit l2 enters through the pipe connection 56. The capillaries 23 also are collected together by a pipe 57, which leads back to the compressor in the form of the conduit 4.

FIG. 6 shows the idealised TS-diagram of the refrigeration machine circuit. T defines the freezing point of the water, T is the crystallisation temperature of the storage device which has to lie above the freezing point by an amount such that the evaporator temperature T, does not fall below the freezing point of the water T T shows the temperature of the compressed gas which, in dependence upon the surface area of the condenser 1, has to lie several degrees above the external ambient temperature T,,.

4 FIG. 7 shows (right hand portion) the relationship The left hand portion of the figure illustrates the technical efficiency derived from this ideal Carnot efficiency and the machine losses in dependence upon the size of the machine. As shown therein, this (point 72) amounts to 3.7 for daytime operation and (point 73) 5.2 for night operation. By reason of the phase displacement in time, which the storage device makes possible, the total electric power consumption thus drops by 3U percent in a lOkW installation. For a given operating period a more favourable smaller drive machine can be installed. Since as a rule the cost of power during the hours of night is only approximately 40 percent of the daytime cost, the operating costs thus drop to 28 percent.

Preferably the storage mass utilized in the storage device comprises a hydrate which contains more than 8 MOI of water of crystallization and further may comprise the hydrate of a ionogenic material which contains a variety of metal ions.

I claim:

l. Refrigeration machine circuit comprising a compressor, a condensor, a fan for blowing air over said condensor, an evaporator, a cold water circuit which is in heat change relationship with said evaporator, and a refrigeration storage device, characterized in that said refrigeration storage device contains a storage mass which crystallizes at a temperature above 0 C. and below 8 C., which is in good heat conducting communication with the evaporator, and which has water from the cold water circuit playing on it and in thermal contact with it such that heat may be transferred from said water to said storage mass.

2. Refrigeration machine circuit according to claim 1 characterised in that the storage mass forms a hydrafihvhich ebmain 'indre than 8 MOI of water of crystallisation.

3. Refrigeration machine circuit according-to claim 1, characterised in that the storage mass forms ahydrate of an ionogenic material which contains a variety of metal ions.

4. Refrigeration machine circuit according to claim 1, characterised in that the storage mass is arrangedin thin-walled, vertically extending vessels.

5. Refrigeration machine circuit according to claim 4, characterised in that the vessels consist of thin flexible tubes.

6. Refrigeration machine circuit according to claim 4, characterised in that the vessels form a unit with evaporator channels.

7. Refrigeration machine circuit according to claim 6, characterised in that the evaporator channels are formed by a double walled sheet metal plate.

8..Refrigeration machine circuit according to claim 7, characterised in that the sheet metal plates support the storage mass and are substantially in tension.

9. Refrigeration machine circuit according to claim 8, characterised in that the sheet metal plates which are arranged side by side in a container are so relatively displaced in height that above and below the plates channels are formed which taper when viewed at right angles to the sheet metal plates. 

1. Refrigeration machine circuit comprising a compressor, a condensor, a fan for blowing air over said condensor, an evaporator, a cold water circuit which is in heat change relationship with said evaporator, and a refrigeration storage device, characterized in that said refrigeration storage device contains a storage mass which crystallizes at a temperature above 0* C. and below 8* C., which is in good heat conducting communication with the evaporator, and which has water from the cold water circuit playing on it and in thermal contact with it such that heat may be transferred from said water to said storage mass.
 2. Refrigeration machine circuit according to claim 1, characterised in that the storage mass forms a hydrate which contains more than 8 Mol of water of crystallisation.
 3. Refrigeration machine circuit according to claim 1, characterised in that the storage mass forms a hydrate of an ionogenic material which contains a variety of metal ions.
 4. Refrigeration machine circuit according to claim 1, characterised in that the storage mass is arranged in thin-walled, vertically extending vessels.
 5. Refrigeration machine circuit according to claim 4, characterised in that the vessels consist of thin flexible tubes.
 6. Refrigeration machine circuit according to claim 4, characterised in that the vessels form a unit with evaporator channels.
 7. Refrigeration machine circuit according to claim 6, characterised in that the evaporator channels are formed by a double walled sheet metal plate.
 8. Refrigeration machine circuit according to claim 7, characterised in that the sheet metal plates support the storage mass and are substantially in tension.
 9. Refrigeration machine circuit according to claim 8, characterised in that the sheet metal plates which are arranged side by side in a container are so relatively displaced in height that above and below the plates channels are formed which taper when viewed at right angles to the sheet metal plates. 